1. Field of the Invention
This invention concerns the construction of a spindle to which a ski of a snowmobile is attached. In particular, this invention encompasses a spindle construction that facilitates adjustment of the width of the ski stance for a snowmobile (also known as a “sied”).
2. Description of Related Prior Art
In the prior art, there are at least two known types of skis. The first is called a single-keel ski because it incorporates a single keel having a single or double carbide runners, which runs along a longitudinal part of the length of the underside of the keel. The second conventional ski is called the dual-keel ski because it incorporates a pair of keels which have carbide runners that extend along longitudinal portions of the undersurface of the snowmobile ski at positions laterally disposed apart from one another. For the second type of ski, the two runners typically are disposed one each on the two lateral edges of the keels.
Most snowmobiles that have been made in the last twenty years have included two skis at the front for turning the vehicle. The ski stance for snowmobiles is determined as the distance (or width) between the two skis. In particular, where a snowmobile is provided with a pair of single-runner skis, which is the more common example to date, the ski stance is measured as the distance (or width) between the carbide runners at the bottoms of the skis. In the case of a snowmobile fitted with a pair of dual-runner skis, the stance is measured as the distance between the centerlines of the skis (or some other suitable convention).
Conventionally, snowmobiles are manufactured with a pre-set ski stance. Depending on the type of terrain in which the snowmobile is used, the pre-set ski stance may have either a positive or a negative effect on the performance of the snowmobile.
As a general rule, there are two basic types of riding conditions for snowmobiles. Each of these two riding conditions places different demands on the snowmobile. Accordingly, each requires a different ski stance.
The first type of riding condition is the groomed trail. Groomed trails include a base of compacted snow, generally with a layer of loose snow above the compacted snow. Because the groomed trail has a solid, compacted base layer, the carbide runners on the bottoms of the snowmobile skis are generally always in contact with the compacted surface. The carbide runners, therefore, provide the edge upon which a turn may be executed. For maximum stability of the snowmobile on a groomed trail, the ski stance is usually pre-set to the widest distance possible. The maximum width of the snowmobile, set by SSCC (Snowmobile Safety Certification Committee), a safety group in the United States, is 48 inches. Generally, the maximum width is set so that snowmobiles do not interlock skis when passing one another on groomed trails.
The second type of riding condition, which is antithetical to the first, is mountain terrain. Mountain snowmobiling differs considerably from snowmobiling on groomed trails because the snow is generally loose, powder snow, which is often deeper than the height of the skis. In other words, in mountain conditions, the bottoms of the skis almost never touch the ground. Therefore, the carbide runners do not assist in turning the vehicle as much as when on groomed trails.
In mountain snowmobiling, it is the preferred practice to keep the ski stance to the smallest width possible. A small ski stance facilitates side hilling of the snowmobile. Side hilling is a technique used by mountain snowmobilers to climb the side of a mountain. The technique requires riders to traverse the mountain diagonally, thus, requiring riders to lean the snowmobile into the surface of the mountain to keep the snowmobile in a substantially horizontal position while crisscrossing the selected mountain area. In order to facilitate leaning of the snowmobile, it is preferred to decrease the distance between the ski and the frame (also referred to as the “tunnel”) of the snowmobile. This decreases the moment applied to the snowmobile by the ski. It also permits the snowmobile to get closer to the side of the mountain. In mountain snowmobiling, snowmobiles usually traverse wooded areas. Therefore, a narrow ski stance is particularly advantageous, because riders may pass more easily between trees and other obstacles not encountered on groomed trails.
Since the stances for mountain and trail riding conditions are so different from one another, manufacturers currently manufacture different snowmobiles specifically tailored to the specific environment in which they are to be used. Groomed trail snowmobiles are manufactured with the widest stance permissible by the SSCC in order to maintain maximum stability. Mountain snowmobiles, on the other hand, are manufactured with as narrow a stance as possible to facilitate side hilling and also retain the necessary balance of the vehicle while riding.
Because the two types of snowmobiles have such different stances, the average consumer faces a dilemma when purchasing a snowmobile. Purchasers who desire a snowmobile that will handle optimally both on groomed trails and on mountain terrain will not find such a vehicle commercially available. In addition, purchasers located in areas where there is significant snowfall and few trails, while they may require a mountain snowmobile to navigate local conditions, may not desire a snowmobile designed specifically for climbing hills and mountains. For consumers that live in heavy snowfall areas and do not necessarily engage in mountain climbing but do engage off-trail riding, a higher degree of stability can be achieved by increasing the narrow stance of a conventional mountain sled.
One way to alter the ski stance of a conventional snowmobile is to increase or decrease the distance between the frame and the spindle holder by altering the length of the lower arm assembly and the upper arm assembly, both of which attach the spindle holder to the frame. Although this alters the ski stance of the snowmobile, such a modification requires realignment of the steering rod and the stabilizer bar. This modification also necessitates readjustment of the shock assembly because of the many parts that individually connect to the arm at a predetermined distance from the frame.
As will be appreciated by those skilled in the art, while it is possible to modify a snowmobile's stance, it is not possible to do so at present without significant effort.
A need has, therefore, arisen for a snowmobile ski spindle, which offers a quick and easy way to convert a snowmobile's ski stance without having to re-adjust other parameters of the snowmobile's front suspension system.